Core promoter mutation of nucleotides A1762T and G1764A of hepatitis B virus increases core promoter transactivation by hepatocyte nuclear factor 1.

Hepatitis B virus (HBV) infection highly increases the risk for liver cirrhosis and hepatocellular carcinoma (HCC). The clinical manifestation of HBV infection is determined by the mutual interplay of the viral genotype, host genetic factors, mode of transmission, adaptive mutations, and environmental factors. Core promoter activation plays a critical role in the pre-genomic RNA transcription of HBV for HBV replication. The mutations of core promoter have been implicated in HCC development. We had obtained HBV genes from Myanmar HBV infectants and identified gene variations at the core promoter region. For measuring the relative transactivation activity on core promoter, we prepared the core-promoter reporter construct. Both of A1762T and G1764A mutation were consistently found in the HBV genes with hepatocellular carcinoma. The A1762T/G1764A mutation was corresponding to K130M/V131I of HBx protein. We prepared the core promoter-luciferase reporter construct containing the double A1762T/G1764A mutation and the K130M/V131I HBx protein expression construct. The A1762T/G1764A mutation highly was responsive to core promoter transactivation by HBx, regardless of HBx mutation. The A1762T/G1764A mutation newly created hepatocyte nuclear factor 1 (HNF1) responsive element. Ectopic expression of HNF1 largely increased the HBV core promoter containing A1762T/G1764A mutation. In addition, hepatic rich fatty acid, palmitic acid and oleic acid, increased K130M/V131I HBx level by core promoter activation. These results provide biological properties and clinical significance of specific HBV core promoter mutants related with HCC development.

Transcriptional Regulation of the Angptl8 Gene by Hepatocyte Nuclear Factor-1 in the Murine Liver.

Brief refeeding times (~60 min) enhanced hepatic Angptl8 expression in fasted mice. We cloned the mouse Angptl8 promoter region to characterise this rapid refeeding-induced increase in hepatic Angptl8 expression. Deletion of the -309/-60 promoter region significantly attenuated basal promoter activity in hepatocytes. A computational motif search revealed a potential binding motif for hepatocyte nuclear factor 1α/1ß (HNF-1α/ß) at -84/-68 bp of the promoter. Mutation of the HNF-1 binding site significantly decreased the promoter activity in hepatocytes, and the promoter carrying the mutated HNF-1 site was not transactivated by co-transfection of HNF-1 in a non-hepatic cell line. Silencing Hnf-1 in hepatoma cells and mouse primary hepatocytes reduced Angptl8 protein levels. Electrophoretic mobility-shift assays confirmed direct binding of Hnf-1 to its Angptl8 promoter binding motif. Hnf-1α expression levels increased after short-term refeeding, paralleling the enhanced in vivo expression of the Angptl8 protein. Chromatin immunoprecipitation (ChIP) confirmed the recruitment of endogenous Hnf-1 to the Angptl8 promoter region. Insulin-treated primary hepatocytes showed increased expression of Angptl8 protein, but knockdown of Hnf-1 completely abolished this enhancement. HNF-1 appears to play essential roles in the rapid refeeding-induced increases in Angptl8 expression. HNF-1α may therefore represent a primary medical target for ANGPTL8-related metabolic abnormalities. The study revealed the transcriptional regulation of the mouse hepatic Angptl8 gene by HNF-1.

HNF-1 binding point mutation of the AFP gene promotes cirrhosis in post-menopausal women.

OBJECTIVE: α-fetoprotein (AFP) expression is activated during the embryonic stage or hepatocellular carcinogenesis, so it is presumed that AFP is a key endogenous molecule to promote cell proliferation or differentiation. We carried out gene screening in an unknown family with hyper-alpha-fetoproteinemia and some sporadic menopausal women, and discussed the relationship between AFP expression and liver cirrhosis. METHODS: Peripheral blood samples from family members, patients with malignant liver tumors, and normal controls were collected. Full-length sequence of AFP was amplified and directly sequenced, and compared with normal controls. HNF-1α and HNF-1ß in plasma levels of family members, patients with liver cancer, newborns, pregnant women, and normal subjects were detected by ELISA, and the relationship between HNF-1 and AFP mutation or high expression was evaluated. RESULTS: There was a mutation in AFP promoter region at c.-200 C>T, which was located at the binding site of AFP hepatocyte nuclear factor 1 (HNF-1). AFP was higher than 4000 ng/L in all members carrying the mutation, but liver cancer was excluded in the family with hyper-alpha-fetoprotein. However, cirrhosis occurred in post-menopausal women. The cases reviewed showed that unknown hyper-alpha-fetoprotein was closely related to HNF-1 binding point of AFP in post-menopausal women with cirrhosis (7/11), while the plasma levels of HNF-1α and HNF-1ß were not significantly different. CONCLUSION: The mutation of the HNF-1 binding point of AFP may lead to an abnormal high expression of AFP by altering the binding of HNF transcription factors, which is closely related to cirrhosis in menopausal women.

Acetaminophen-induced hepatocyte injury: C2-ceramide and oltipraz intervention, hepatocyte nuclear factor 1 and glutathione S-transferase A1 changes.

Acetaminophen (APAP) is an antipyretic and analgesic, which is commonly associated with drug-induced hepatic injury. C2-ceramide plays a key role in mediating cell life activities, and oltipraz was extensively studied as a cancer chemopreventive agent. Glutathione S-transferase A1 (GSTA1) acts as a vital liver detoxification enzyme. Hepatocyte nuclear factor 1 (HNF-1) regulates various cellular signaling pathways. In this study, we investigated the effects of C2-ceramide and oltipraz on APAP-induced hepatocyte injury and the changes of HNF-1 and GSTA1. Results showed that C2-ceramide (6 µmol/L) exacerbated APAP-induced hepatocyte injury and caused a significant decrease (P < .01) in HNF-1 and GSTA1 expressions. Meanwhile, GSTA1 content in supernatant was significantly increased (P < .01). In contrast, oltipraz (8 µmol/L) reduced the injury and significantly elevated (P < .01) HNF-1 and GSTA1 expressions while GSTA1 content in supernatant was significantly decreased (P < .01). In conclusion, these findings revealed that C2-ceramide inhibited HNF-1 and GSTA1 expression and exacerbated hepatocyte injury, while oltipraz treatment results in the reduction of hepatocyte injury, and promoted HNF-1 and GSTA1 expression. Additionally, the changes in HNF-1 and GSTA1 were related to APAP-induced hepatocyte injury. These results were useful to investigate the mechanism of an antipyretic and analgesic drug combination.

[Clinical phenotypes of hepatocyte nuclear factor 1 homeobox b-associated disease].

Objective: Hepatocyte nuclear factor 1 homeobox b (HNF1B) -associated disease is an autosomal dominant inherited disorder with a variable, multi-systemic phenotype. In China, five adult probands and one child proband with HNF1B-associated disease had been reported, whereas few fetuses are described. The aims of this retrospective study were to understand about the clinical manifestations of HNF1B-associated disease and to further improve the recognition of this disorder. Method: Four patients (3 males, 1 female) and three fetuses with HNF1B mutations were included in this study. They were admitted to our hospital from January 2013 to March 2017. HNF1B mutations were detected using targeted next generation sequencing and quantitative real-time PCR or Sanger sequencing. HNF1B heterozygous deletion of exons 1-9 was found in 4 patients and 2 fetuses, and HNF1B heterozygous missense mutation in 1 fetus. These two mutations had been reported. Two patients and 1 fetus had de novo mutations. Results of renal ultrasonography with or without magnetic resonance imaging, biochemical investigations, urine routine examination and other necessary investigations in 7 cases were analyzed. Result: Three patients were Han Chinese ethnicity, and one patient was Mongolian. In patients 1 and 4, abnormal fetal kidneys were discovered by routine ultrasonography, and the age at first feature identified in Patients 2 and 3 were 13 years and 28 years. Patient 3 had normal renal function and the remainder had reduced glomerular filtration rate. In addition, patient 4 presented with nephrotic syndrome and glycosuria, patient 2 with early onset hyperparathyroidism and renal osteodystrophy, and patient 3 with diabetes mellitus. All the 4 patients had renal structural abnormalities including bilateral multiple renal cysts, dysplasia and hyperechogenic kidneys. Only patient 3 had a positive family history of renal diseases, the remainder had a negative family history of renal diseases. In 3 fetuses, prenatal ultrasound anomalies were detected during the second trimester. These 3 fetuses had hyperechogenic kidneys with or without renal cysts. Polyhydramnios was detected in only one of the 3 fetuses. Two of the 3 fetuses had a positive family history of renal diseases. Conclusion: Clinical phenotypes of HNF1B-related disease are heterogeneous, renal malformations clearly appear to be the most common manifestation, multiple renal cysts are characteristic, and patients can progress to impaired kidney function during childhood; HNF1B mutation is a differential diagnosis of fetal hyperechogenic kidneys or multiple renal cysts.

Hepatic HNF1 transcription factors control the induction of PCSK9 mediated by rosuvastatin in normolipidemic hamsters.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) impedes low­density lipoprotein (LDL) receptor (LDLR)-mediated LDL-cholesterol uptake and has hence emerged as a critical regulator of serum cholesterol levels and a new therapeutic target for the treatment of hypercholesterolemia. Statins have been shown to elevate circulating PCSK9 levels by stimulating PCSK9 gene transcription, which reduces the clinical efficacy of statin in LDL­cholesterol reduction. The transcription of PCSK9 is partially controlled by the hepatocyte nuclear factor 1 (HNF1) binding site embedded in the proximal region of its promoter. In this study, we utilized adenoviral shRNA delivery vectors to generate liver-specific knockdown of HNF1α (Ad­shHNF1α) or HNF1ß (Ad­shHNF1ß) in hamsters to examine the impact of reduced hepatic expression of HNF1 transcription factors on statin­induced elevation of PCSK9 expression and serum cholesterol levels. We showed that the administration of rosuvastatin (RSV) to normolipidemic hamsters significantly augmented hepatic PCSK9 expression and serum PCSK9 levels. In addition, RSV treatment increased hepatic HNF1α protein levels without a clear effect on HNF1α mRNA expression. Injection of Ad-shHNF1α or Ad­shHNF1ß into hamsters both blunted RSV­induced elevation of PCSK9 serum concentration and hepatic mRNA and protein levels, which led to significant increases in liver LDLR protein abundance. Furthermore, hepatic depletion of HNF1 factors lowered circulating total cholesterol and non­high density lipoprotein cholesterol levels in RSV­treated hamsters. Our study demonstrates that both HNF1α and HNF1ß are positive regulators of hepatic PCSK9 transcription in hamster species and that transient, liver-specific knockdown of either HNF1α or HNF1ß could antagonize the RSV­induced elevation of serum PCSK9 and reduce circulating cholesterol levels.

Isolation and expansion of cytokeratin positive progenitor cells from adult murine pancreatic ducts expressing Pdx-1, Nestin, Sox9, MafA and hepatic nuclear factors.

BACKGROUND: Recent studies suggest that stem cells may represent a putative source for the generation of beta cells. However, the identity and characteristics of stem cells from adult pancreas and conditions for their large scale expansion are still poorly defined. METHODS: DPC were isolated from adult pancreatic ducts of C57Bl/6 mice. Expression profile was investigated by PCR, FACS and immunohistochemistry. RESULTS: DPC express a panel of stem cell associated markers such as Pdx-1, cytokeratin-19 (CK19), nestin, Sox9 together with the transcription factor MafA and hepatic nuclear factors HNF1ß, HNF3ß, HNF4α und HNF6. This gene expression profile is suggesting that DPC might be a promising tool for endocrine differentiation. After stimulation with picolinic acid and hypoxia, DPC expressed the endocrine differentiation marker Ngn3. Nevertheless, insulin production was not observed. CONCLUSIONS: We here describe a protocol for the isolation end expansion of murine pancreatic ductal progenitor cells (DPC) displaying high self-renewal, spheroid- and colony-forming capacity. Further studies are required to elucidate the conditions for differentiation into mature pancreatic endocrine cell lineages.

HNF1 regulates critical processes in the human epididymis epithelium.

The luminal environment of the epididymis participates in sperm maturation and impacts male fertility. It is dependent on the coordinated expression of many genes encoding proteins with a role in epithelial transport. We identified cis-regulatory elements for critical genes in epididymis function, by mapping open chromatin genome-wide in human epididymis epithelial (HEE) cells. Bioinformatic predictions of transcription factors binding to the regulatory elements suggested an important role for hepatocyte nuclear factor 1 (HNF1) in the transcriptional program of these cells. Chromatin immunoprecipitation and deep sequencing (ChIP-seq) revealed HNF1 target genes in HEE cells. In parallel, the contribution of HNF1 to the transcriptome of HEE cells was determined by RNA-seq, following siRNA-mediated depletion of both HNF1α and HNF1ß transcription factors. Repression of these factors caused differential expression of 1892 transcripts (902 were downregulated and 990 upregulated) in comparison to non-targeting siRNAs. Differentially expressed genes with HNF1 ChIP-seq peaks within 20 kb were subject to gene ontology process enrichment analysis. Among the most significant processes associated with down-regulated genes were epithelial transport of water, phosphate and bicarbonate, all critical processes in epididymis epithelial function. Measurements of intracellular pH (pHi) confirmed a role for HNF1 in regulating the epididymis luminal environment.

Transcriptional Regulation of Cytosolic Sulfotransferase 1C2 by Intermediates of the Cholesterol Biosynthetic Pathway in Primary Cultured Rat Hepatocytes.

Cytosolic sulfotransferase 1C2 (SULT1C2) is expressed in the kidney, stomach, and liver of rats; however, the mechanisms regulating expression of this enzyme are not known. We evaluated transcriptional regulation of SULT1C2 by mevalonate (MVA)-derived intermediates in primary cultured rat hepatocytes using several cholesterol synthesis inhibitors. Blocking production of mevalonate with the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor pravastatin (30 µM), reduced SULT1C2 mRNA content by ∼40% whereas the squalene synthase inhibitor squalestatin (SQ1, 0.1 µM), which causes accumulation of nonsterol isoprenoids, increased mRNA content by 4-fold. Treatment with MVA (10 mM) strongly induced SULT1C2 mRNA by 12-fold, and this effect was blocked by inhibiting squalene epoxidase but not by more distal cholesterol inhibitors, indicating the effects of MVA are mediated by postsqualene metabolites. Using rapid amplification of cDNA ends (RACE), we characterized the 5' end of SULT1C2 mRNA and used this information to generate constructs for promoter analysis. SQ1 and MVA increased reporter activity by ∼1.6- and 3-fold, respectively, from a construct beginning 49 base pairs (bp) upstream from the longest 5'-RACE product (-3140:-49). Sequence deletions from this construct revealed a hepatocyte nuclear factor 1 (HNF1) element (-2558), and mutation of this element reduced basal (75%) and MVA-induced (30%) reporter activity and attenuated promoter activation following overexpression of HNF1α or 1ß. However, the effects of SQ1 were localized to a more proximal promoter region (-281:-49). Collectively, our findings demonstrate that cholesterol biosynthetic intermediates influence SULT1C2 expression in rat primary hepatocytes. Further, HNF1 appears to play an important role in mediating basal and MVA-induced SULT1C2 transcription.

Screening of diabetes of youth for hepatocyte nuclear factor 1 mutations: clinical phenotype of HNF1ß-related maturity-onset diabetes of the young and HNF1α-related maturity-onset diabetes of the young in Japanese.

AIM: To compare the prevalence and clinical features of HNF1ß-related MODY and HNF1α-related MODY in Japanese. METHODS: We enrolled 230 Japanese patients with suspected MODY and examined them for HNF1α and HNF1ß mutations. We characterized the clinical features of HNF1ß-related MODY (HNF1ß-MODY) and HNF1α-related MODY (HNF1α-MODY). RESULTS: Six patients had HNF1ß mutations, four of which were large gene deletions and 24 patients had HNF1α mutations, which included one gene deletion. The mean fasting plasma glucose level at onset of HNF1ß-MODY was considerably higher and the age of onset of HNF1ß-MODY was considerably older than they were for HNF1α-MODY, while the mean BMI and C-peptide index at onset were similar. Three patients with HNF1ß-MODY were found to have dorsal pancreatic agenesis and four of them had whole-gene deletion. Five of the patients with HNF1ß-MODY had insulin secretion defects and were treated with insulin, and four of these did not have a parent with overt diabetes. CONCLUSION: HNF1ß-MODY may present as ß-cell dysfunction in Japanese rather than as hyperinsulinaemia, which it does among European/American. This dysfunction might result from an intrinsically lower capacity for insulin secretion in Japanese. HNF1ß-MODY has an older age of onset than HNF1α-MODY, which may suggest lower penetrance of the disease. In addition, HNF1ß-MODY has a broad spectrum of clinical manifestations, some of which are detectable by imaging. This may be helpful in some cases for selecting HNF1ß-MODY candidates for genetic testing.

Epigenetic determinants of ovarian clear cell carcinoma biology.

Targeted approaches have revealed frequent epigenetic alterations in ovarian cancer, but the scope and relation of these changes to histologic subtype of disease is unclear. Genome-wide methylation and expression data for 14 clear cell carcinoma (CCC), 32 non-CCC and four corresponding normal cell lines were generated to determine how methylation profiles differ between cells of different histological derivations of ovarian cancer. Consensus clustering showed that CCC is epigenetically distinct. Inverse relationships between expression and methylation in CCC were identified, suggesting functional regulation by methylation, and included 22 hypomethylated (UM) genes and 276 hypermethylated (HM) genes. Categorical and pathway analyses indicated that the CCC-specific UM genes were involved in response to stress and many contain hepatocyte nuclear factor (HNF) 1-binding sites, while the CCC-specific HM genes included members of the estrogen receptor alpha (ERalpha) network and genes involved in tumor development. We independently validated the methylation status of 17 of these pathway-specific genes, and confirmed increased expression of HNF1 network genes and repression of ERalpha pathway genes in CCC cell lines and primary cancer tissues relative to non-CCC specimens. Treatment of three CCC cell lines with the demethylating agent Decitabine significantly induced expression for all five genes analyzed. Coordinate changes in pathway expression were confirmed using two primary ovarian cancer datasets (p < 0.0001 for both). Our results suggest that methylation regulates specific pathways and biological functions in CCC, with hypomethylation influencing the characteristic biology of the disease while hypermethylation contributes to the carcinogenic process.

Hepatocyte nuclear factor 1 regulates the expression of the organic cation transporter 1 via binding to an evolutionary conserved region in intron 1 of the OCT1 gene.

The organic cation transporter 1 (OCT1), also known as solute carrier family 22 member 1, is strongly and specifically expressed in the human liver. Here we show that the hepatocyte nuclear factor 1 (HNF1) regulates OCT1 transcription and contributes to the strong, liver-specific expression of OCT1. Bioinformatic analyses revealed strong conservation of HNF1 binding motifs in an evolutionary conserved region (ECR) in intron 1 of the OCT1 gene. Electrophoretic mobility shift and chromatin immunoprecipitation assays confirmed the specific binding of HNF1 to the intron 1 ECR. In reporter gene assays performed in HepG2 cells, the intron 1 ECR increased SV40 promoter activity by 22-fold and OCT1 promoter activity by 13-fold. The increase was reversed when the HNF1 binding sites in the intron 1 ECR were mutated or the endogenous HNF1α expression was downregulated with small interfering RNA. Following HNF1α overexpression in Huh7 cells, the intron 1 ECR increased SV40 promoter activity by 11-fold and OCT1 promoter activity by 6-fold. Without HNF1α overexpression, the increases were only 3- and 2-fold, respectively. Finally, in human liver samples, high HNF1 expression was significantly correlated with high OCT1 expression (r = 0.48, P = 0.002, n = 40). In conclusion, HNF1 is a strong regulator of OCT1 expression. It remains to be determined whether genetic variants, disease conditions, or drugs that affect HNF1 activity may affect the pharmacokinetics and efficacy of OCT1-transported drugs such as morphine, tropisetron, ondansetron, tramadol, and metformin. Beyond OCT1, this study demonstrates the validity and usefulness of interspecies comparisons in the discovery of functionally relevant genomic sequences.

Association and expression analysis of porcine HNF1A gene related to meat and carcass quality traits.

The aim of this study was to investigate the association and expression of HNF1A gene as a candidate gene for meat and carcass quality traits in pigs. Statistical analysis revealed that the g.8260 A>G polymorphism significantly associated with pH 24(H), meat percentage and muscle area in the F2 Duroc × Pietrain (DuPi, n=313) and with pH 24(L), fat area and backfat thickness in the Pietrain (Pi, n=110) population. HNF1A mRNA and protein expressions were higher (p<0.05) in animals with the low post-mortem muscle pH 24(L). The promoter methylation profiling suggested that methylation was not involved on HNF1A expression regulation (p>0.05) in animal with divergent muscle pH. In conclusion, polymorphism in porcine HNF1A gene could be used as a candidate marker to improve the meat and carcass quality traits, with the consideration of breed-specific effect.

Characterization of P1 promoter activity of the beta-galactoside alpha2,6-sialyltransferase I gene (siat 1) in cervical and hepatic cancer cell lines.

The level of beta-galactoside alpha2,6-sialyltransferase I (ST6Gal I) mRNA, encoded by the gene siat1, is increased in malignant tissues. Expression is regulated by different promoters - P1, P2 and P3 - generating three mRNA isoforms H, X and YZ. In cervical cancer tissue the mRNA isoform H, which results from P1 promoter activity, is increased. To study the regulation of P1 promoter, different constructs from P1 promoter were evaluated by luciferase assays in cervical and hepatic cell lines. Deletion of a fragment of 1048 bp (-89 to +24 bp) increased 5- and 3-fold the promoter activity in C33A and HepG2 cell lines, respectively. The minimal region with promoter activity was a 37 bp fragment in C33A cells. The activity of this region does not require the presence of an initiator sequence. In HepG2 cells the minimal promoter activity was detected in the 66 bp fragment. Sp1 (-32) mutation increased the promoter activity only in HepG2 cells. HNF1 mutation decreased promoter activity in HepG2 cell line but not in C33A cells. We identified a large region that plays a negative regulation role. The regulation of promoter activity is cell type specific. Our study provides new insights into the complex transcriptional regulation of siat1 gene.

Risk of carcinoma in women with ovarian endometrioma.

Endometriosis affects an estimated 10% of women in the reproductive-age group. Here, we review current knowledge on molecular genesis of endometriosis-associated epithelial ovarian carcinoma (EOC). This article reviews the English language literature for biology, pathogenesis, and pathophysiological studies on endometriosis-associated EOC. Although endometriosis generally remains a benign condition, it demonstrates somatically acquired genetic alterations. Clear cell carcinoma (CCC) and endometrioid adenocarcinoma (EAC) are the most frequent types of EOC associated with endometriosis. Retrograde menstruation or ovarian hemorrhage carries highly pro-oxidant factors, such as iron, into the peritoneal cavity or ovarian endometrioma. CCC and EAC should be considered separately in studies of endometriosis-associated EOC. The repeated events of hemorrhage in endometriosis can contribute to carcinogenesis and progression via 3 major processes: 1) increasing oxidative stress promotes DNA methylation; 2) activating anti-apoptotic pathways supports tumor promotion; and 3) aberrant expression of stress signaling pathways contributes to tumor progression. This review summarizes recent advances in the understanding of epidemiology, carcinogenesis, pathogenesis, and pathophysiology of endometriosis-associated EOC; and a possible novel model is proposed.

An ancient mechanism of hindbrain patterning has been conserved in vertebrate evolution.

The hindbrain is a vertebrate-specific embryonic structure of the central nervous system formed by iterative transitory units called rhombomeres (r). Rhombomeric cells are segregated by interhombomeric boundaries which are prefigured by sharp gene expression borders. The positioning of the first molecular boundary within the hindbrain (the prospective r4/r5 boundary) responds to the expression of an Iroquois (Irx) gene in the anterior (r4) and the gene vHnf1 at the posterior (r5). However, while Irx3 is expressed anteriorly in amniotes, a novel Irx gene, iro7, acts in teleosts. To assess the evolutionary history of the genes responsible for the positioning of the r4/r5 boundary in vertebrates, we have stepped outside the gnathostomes to investigate these genes in the agnathans Lethenteron japonicum and Petromyzon marinus. We identified one representative of the Hnf1 family in agnathans. Its expression pattern recapitulates that of vHnf1 and Hnf1 in higher vertebrates. Our phylogenetic analysis places this gene basal to gnathostome Hnf1 and vHnf1 genes. We propose that the duplication of an ancestral hnf1 gene present in the common ancestor of agnathans and gnathostomes gave rise to the two genes found in gnathostomes. We have also amplified 3 Irx genes in L. japonicum: LjIrxA, LjIrxC, LjIrxD. The expression pattern of LjIrxA (the agnathan Irx1/3 ortholog) resembles those of Irx3 or iro7 in gnathostomes. We propose that an Irx/hnf1 pair already present in early vertebrates positioned the r4/r5 boundary and that gene duplications occurred in these gene families after the divergence of the agnathans.

Resveratrol potentiates glucose-stimulated insulin secretion in INS-1E beta-cells and human islets through a SIRT1-dependent mechanism.

Resveratrol, a polyphenol compound, is known for its effects on energy homeostasis. With properties of energy sensors mediating effects of calorie restriction, sirtuins are targets of resveratrol. The mammalian sirtuin homolog SIRT1 is a protein deacetylase playing a role in glucose metabolism and islet function. Here, we investigated the effects of resveratrol and possible link with SIRT1 in ß-cells. Insulinoma INS-1E cells and human islets were cultured with resveratrol before analyzing their physiological responses. Treatment of INS-1E cells for 24 h with 25 µM resveratrol resulted in marked potentiation of glucose-stimulated insulin secretion. This effect was associated with elevated glycolytic flux, resulting in increased glucose oxidation, ATP generation, and mitochondrial oxygen consumption. Such changes correlated with up-regulation of key genes for ß-cell function, i.e. Glut2, glucokinase, Pdx-1, Hnf-1α, and Tfam. In human islets, chronic resveratrol treatment similarly increased both the glucose secretory response and expression of the same set of genes, eventually restoring the glucose response in islets obtained from one type 2 diabetic donor. Overexpression of Sirt1 in INS-1E cells potentiated resveratrol effects on insulin secretion. Conversely, inhibition of SIRT1 achieved either by expression of an inactive mutant or by using the EX-527 inhibitor, both abolished resveratrol effects on glucose responses. Treatment of INS-1E cells with EX-527 also prevented resveratrol-induced up-regulation of Glut2, glucokinase, Pdx-1, and Tfam. Resveratrol markedly enhanced the glucose response of INS-1E cells and human islets, even after removal of the compound from the medium. These effects were mediated by and fully dependent on active SIRT1, defining a new role for SIRT1 in the regulation of insulin secretion.

Hepatocellular carcinoma: New and emerging risks.

The underlying liver diseases that put patients at risk for the development of hepatocellular carcinoma (HCC) are well known. However, it is equally well known that not all patients with these conditions will develop HCC. Therefore within the disease groups (hepatitis B, cirrhosis, etc.,) there are other factors that indicate greater or lesser risk. Some markers of risk are common to all causes of HCC, such as cellular dysplasia, advancing age and male gender. Others factors are specific to individual diseases. This has been well established for hepatitis B in which viral load, genotype and antigen status are major contributors to increased risk of HCC. For both hepatitis B and hepatitis C attempts have been made to identify those individuals at greatest risk using data from large cohort studies. In addition to the common causes of liver disease that are recognized to be causes of HCC non-alcoholic fatty liver disease and possibly diabetes are newly emerging risk factors.

Subtype classification of hepatocellular adenoma.

Hepatocellular adenomas (HCA) are rare benign tumours occurring mainly in women under oral contraceptives. HCA bleed frequently and transform rarely into hepatocellular carcinoma. Identification of genes recurrently mutated in HCA and good genotype/phenotype correlations provided the basis of a pathomolecular classification of different HCA subgroups, characterized using immunohistochemical markers. HNF1A-mutated HCA: Biallelic-inactivating mutations of HNF1A gene are identified in 35-40% of HCA. HNF1alpha-inactivated HCA display characteristic pathological features, including marked steatosis. The expression of FABP1 (which is a HNF1A target gene) is downregulated and the absence of L-FABP expression diagnosed this subgroup. beta-Catenin-mutated HCA: beta-catenin mutations leading to activation of the Wnt/beta-catenin pathway represented 10-15% of HCA. They are characterized by overexpression of glutamine synthetase and aberrant nuclear beta-catenin staining. These beta-catenin-activated HCA are at greater risk of malignant transformation; they are difficult to differentiate from well-differentiated HCC. Inflammatory HCA (50%): These are defined by the presence of inflammatory infiltrates, sinusoidal dilatation and thick-walled arteries. Small in-frame deletions that target the binding site of gp130 for IL-6 have been reported in 60% of inflammatory HCA. There is an overexpression of the inflammatory proteins serum amyloid A and C-reactive protein in tumour hepatocytes both at mRNA and protein levels. Inflammatory HCA occurred more frequently in patients with high body mass index; they can be also mutated for beta-catenin and therefore are probably at risk of HCC. Unclassified HCA: Less than 10% of HCA do not express any of the above-mentioned phenotypic markers. Taking into account noticeable differences between the HCA subgroups, in terms of clinical and prognostic features, phenotyping may become an important tool for HCA management strategy.

Regulation of UGT1A1 and HNF1 transcription factor gene expression by DNA methylation in colon cancer cells.

BACKGROUND: UDP-glucuronosyltransferase 1A1 (UGT1A1) is a pivotal enzyme involved in metabolism of SN-38, the active metabolite of irinotecan commonly used to treat metastatic colorectal cancer. We previously demonstrated aberrant methylation of specific CpG dinucleotides in UGT1A1-negative cells, and revealed that methylation state of the UGT1A1 5'-flanking sequence is negatively correlated with gene transcription. Interestingly, one of these CpG dinucleotides (CpG -4) is found close to a HNF1 response element (HRE), known to be involved in activation of UGT1A1 gene expression, and within an upstream stimulating factor (USF) binding site. RESULTS: Gel retardation assays revealed that methylation of CpG-4 directly affect the interaction of USF1/2 with its cognate sequence without altering the binding for HNF1-alpha. Luciferase assays sustained a role for USF1/2 and HNF1-alpha in UGT1A1 regulation in colon cancer cells. Based on the differential expression profiles of HNF1A gene in colon cell lines, we also assessed whether methylation affects its expression. In agreement with the presence of CpG islands in the HNF1A promoter, treatments of UGT1A1-negative HCT116 colon cancer cells with a DNA methyltransferase inhibitor restore HNF1A gene expression, as observed for UGT1A1. CONCLUSIONS: This study reveals that basal UGT1A1 expression in colon cells is positively regulated by HNF1-alpha and USF, and negatively regulated by DNA methylation. Besides, DNA methylation of HNF1A could also play an important role in regulating additional cellular drug metabolism and transporter pathways. This process may contribute to determine local inactivation of drugs such as the anticancer agent SN-38 by glucuronidation and define tumoral response.